1996 Mazda MX3 Egine knocks and stalls out

Engine Mechanical problem
1996 Mazda MX3 4 cyl Automatic 246000 miles

I have a 1996 mx-3. The car has worked fine since I bought it a few months ago but yesterday it started acting funny. It started cutting in and out on the highway when I was accelerating uphill. It smoothed out after a few times and seemed to work ok. When I got home I took a look under the hood. There is now a knock coming from either the crankshaft or the rod bearings. I think. The car worked great this morning and this afternoon until the drive home. This time it started cutting out on the highway on the same hill and the car died out. The oil light flashed on a split second before the car died. I thought maybe I was out of gas so I put some in and had no luck. The car would wind over but not start. After about ten times the car would start and allow me to rev up to about 4000 rpms and then it would just die. I called a tow truck. When I got home to look at the car again, I checked the spark plugs which were just changed about a month ago. They seemed like new. I checked the intake and noticed that there was oil in the hose, the throttle body and the pcv valve. I am not sure if this was there from a previous problem and was maybe never cleaned out. After checking these things, I tried the car again. It started up and idled just fine. The car had been sitting for about an hour and a half by this point. I am trying to figure out what would make the car act this way. Please help. I cannot find another 4 cyl for this car anywhere around here.